RailsBridge has organized a Rails 3 Bugmash on January 16th and 17th. The idea is to try and upgrade your apps and favourite plugins/gems to work with Rails 3 and make the upgrade path as smooth as possible for everyone else by documenting the process and fixing the bugs you encounter. Rails core team and others will be around in #railsbridge to help out the participants during the bugmash. Check the RailsBridge announcement for more details.